The present invention relates to secondary battery (lithium battery) for vehicle or for power supply, particularly to a multi-series battery control system for managing the condition of the secondary battery (lithium battery).
In order to solve a problem that higher precision voltage sensing involves cost increase of insulation means installed for each of multiple lower control units, there has been proposed a storage battery unit aiming at cost reduction by reducing the number of insulation means, for example, refer to Japanese Patent Laid-open 2003-70179, especially pages 3-4, FIG. 1. This Patent Document aims to lower the effect of disturbance such as noise and thereby improve reliability and enable higher precision voltage sensing.